You have to understand this is a Halloween event (Hence Halloween Haunt), and the decorations are meant to be spooky. This seems like you would go up to someone who has decorated their house for Halloween and ask them to take it all down because of what you believe. Its not meant to be hellish or anything, just scary and fun. If you take it THIS seriously, don't go. Simple enough. The actors are not going to now whether you want to be scared or not, but they are going to assume so because you are at Halloween Haunt. If you are offended just by coffins, you REALLY shouldn't go. If you REALLY want to ride the rides, just ignore everything else and ride. Otherwise, wait until spring, so you won't have to be offended.
Its also kind of sad how you think people should be fired and the event should be cancelled just because you are offended by something that the majority (Probably 98%) of people would not find offensive. If you find it offensive, I'll say it again, don't go. If you can't see where you're going, walk carefully.
Also, you say they don't know how to make it "enjoyable." I sure do find it enjoyable because I want to be scared. This isn't an event for just riding the rides... that was during the summer. This is mainly for going through the Halloween attractions. People who go there want to be scared, therefore making it enjoyable. Halloween Haunt is NOTHING compared to some other places I've been to or seen on TV.
You don't just go to a haunted house to look at the walls. This is basically what you're saying.